Donald Trump branded outgoing CIA chief Brennan “the leaker of fake news” after he told Trump to grasp the “Russia threat” instead of “talking and tweeting,” stirring up another feud between the incoming administration and the intelligence community.

Tensions between US President-elect Donald Trump and the intelligence community escalated once again this weekend as outgoing CIA Director John Brennan fiercely attacked Trump’s views on US-Russia rapprochement.

“I don’t think he has a full understanding of Russian capabilities and the actions they are taking on the world,” Brennan said on Fox News Sunday.

With just several days to go until his inauguration, Trump “has to recognize that his words do have impact,” the CIA chief said.

“He’s going to have the opportunity to do something for national security as opposed to talking and tweeting.

“Spontaneity is not something that protects national security interests,” Brennan said in an apparent reference to the widespread perception of Trump as an inexperienced and impulsive politician.

In a matter of hours, Trump responded with a two-tweet outburst questioning whether the CIA director had leaked a recent unsubstantiated dossier to the media. The dossier claims that Russia had gathered compromising personal information about Trump.

“Just look at Syria (red line), Crimea, Ukraine and the build-up of Russian nukes,” Trump wrote on Twitter. “Not good! Was this the leaker of Fake News?”

On January 11, the day after the dossier was released by BuzzFeed, Trump also said on Twitter that intelligence agencies “should never have allowed this fake news to ‘leak’” before asking, “Are we living in Nazi Germany?”

The BuzzFeed publication triggered a week of finger-pointing between Trump and intelligence leadership. On Fox News, Brennan said Trump’s reference to Nazi Germany was an insult to US intelligence officers.

Intelligence agencies should never have allowed this fake news to "leak" into the public. One last shot at me.Are we living in Nazi Germany?

“What I do find outrageous is equating an intelligence community with Nazi Germany,” he said. “I do take great umbrage at that, and there is no basis for Mr. Trump to point fingers at the intelligence community for leaking information that was already available publicly.”

The credibility of the file has been questioned by various top-tier officials. Last Wednesday, Director of National Intelligence James Clapper said after a meeting with Trump that US spy agencies had “not made any judgment that the information in this document is reliable.”

Last week, UK Prime Minister Theresa May commented on BuzzFeed’s statement that the dossier was compiled by a person who is understood to be a former UK intelligence agent. Speaking at a press conference in Downing Street, May said: “It is absolutely clear that the individual who produced this dossier has not worked for the UK government for years.”